Through bulkhead initiators are well known, and commonly employed, particularly, in ordinance applications which have an ordinance transfer line to initiate an explosive type of ordnance device, herein referred to as an "initiator." Such initiators accept a detonating signal from an ordnance transfer device or assembly, and convert the detonating signal to a hot gas output on the downstream side of a solid barrier or bulkhead of the initiator, thereby, producing an "initiation stimulus" for an upstream ordnance subsystem. The bulkhead or barrier is intended to provide a pressure seal during operation of the upstream ordnance sub-system.
The initiation stimulus provided by a through bulkhead initiator is generally transmitted through the bulkhead via shock waves. The initiator generally includes an explosive donor charge of an explosive material which is detonated by the detonating signal. In turn, a shock wave is generated by the detonation of the explosive donor charge, transferred to the bulkhead, and propagated therethrough to an explosive acceptor charge on the upstream side of the bulkhead, and which forms, in part, the upstream ordnance subsystem. The initiator must provide a shock wave of sufficient energy to cause a detonation reaction of the explosive acceptor charge of the upstream ordnance subsystem.
As is well understood in the prior art, the bulkhead or barrier generally comprises a thin member of a larger body which may also serve as a housing which encloses the initiator explosive donor charge and initiator ordnance transfer subassembly. Outer portions of the housing may also serve structural support functions of the upstream ordnance subsystem. Further, portions of the upstream side of the bulkhead may include structural configuration features for receiving the explosive acceptor charge of the upstream ordnance subsystem.
Initiators of the prior art as just described are disclosed in, among others, the following publications: "Development of the Saturn V Thru Bulkhead Initiator," Corwin et al, North American Rockwell Corp., 6th Symposium on Electroexplosive Devices, July 1969; "Through-Bulkhead-lnitiator Development," by Hecks, Sandia Laboratories, Albuquerque, N.M., 6th Pyrotechnic Seminar, 1978; "Thermal Ignition of Pyrotechnics Through a Bulkhead," by Kjeldgaard et al, Sandia Laboratories, Albuquerque, N.M., 8th Symposium on Electroexplosive Devices, 1974; and "Development of a Shock Initiated Through-Bulkhead Actuator," Schwarz et al, Sandia Laboratories, Albuquerque, New Mexico, 6th Pyrotechnic Seminar, 1980.
Further, initiators are also described in, among others, the following U.S. Patents: U.S. Pat. No. 4,608,926, issued to Stevens, entitled, "Swivel Type Through Bulkhead Initiator"; U.S. Pat. No. 4,660,472, issued to Stevens, entitled, "Optical Through Bulkhead Initiator and Safe-Arm Device;" U.S. Pat. No. 4,699,400, issued to Adams, et al, entitled, "Inflator and Remote Sensor with Through Bulkhead Initiator;" U.S. Pat. No. 4,766,726, issued to Tackett, et al, entitled "Segmented Case Rocket Motor;" and U.S. Pat. No. 4,829,765, issued to Bolieau, et al, entitled, "Pulsed Rocket Motor."
Bulkheads or barriers of prior art initiators are generally metallic, commonly stainless steel, and are of sufficient structural size to withstand the passage of the shock wave produced by the detonation of a donor charge without structural degradation. Further, such barriers or bulkheads are also designed to have sufficient structural integrity to withstand both the detonation sequence of the initiator and the operational pressure of an upstream ordinance device.
Developments in the ordnance industry have placed greater demands on the size of the initiator. At the same time, military standards have been imposed as to the type and quantities of explosive donor and acceptor charges, particularly the explosive requirements imposed by U.S. Government Military Standard Mil-Std 1316. More particularly less sensitive donor and explosive acceptor charges must now be used in such initiators.
The latter donor charge requirements affect the relationship between achieving structural integrity of the bulkhead, and at the same time establishing a sufficient shock wave resulting from detonation of the explosive donor charge to detonate the explosive acceptor charge of the upstream ordnance subsystem. Designs meeting Mil-Std 1316 have system length constraints that require reduction of bulkhead thickness. Prior art bulkheads typically use stainless steel barriers that do not exhibit acceptable shock transfer properties or strength to function at operating pressures of, for example, about 5,000 psi, when reduced in size as is required for such designs.
Known devices are limited to substantially thicker bulkheads than that provided by the instant invention as described hereinbelow. Specifically, there is no teaching or suggestion in the art to make a miniaturized bulkhead with a barrier member less than 0.05 inches thick. For example, U.S. Pat. No. 3,945,322 issued Mar. 23, 1976 to Carlson et al. does not provide such a teaching. In fact, Carlson et al. specifically limits that invention to barriers having a thickness of 0.050 to 0.140 of an inch.
The present invention overcomes shortcomings found in the prior art by providing, for the first time, a miniaturized bulkhead having a thickness of less than 0.050 inches, while still providing sufficient structural strength and shock wave properties so as to function with less sensitive explosives meeting the requirements of Mil-Std 1316.